Talk:Cretaceous–Paleogene extinction event

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Featured article Cretaceous–Paleogene extinction event is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.
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Pterosaur[edit]

  • Starting discussion over
  • What about this disputed text? Sidelight12 Talk 18:16, 31 December 2012 (UTC)
  • Recently, new pterosaur taxa have been discovered dating to the Maastrichtian, such as the ornithocheirids Piksi and "Ornithocheirus."[1] This suggests that late Cretaceous pterosaur faunas were far more diverse than previously thought. (p.892)
  • this is not a primary source. It does not mention the KT boundary, but it does show that other pterosaurs were around during the Maastrichtian. This ref does have a lot to do with the existing paragraph. Sidelight12 Talk 18:41, 31 December 2012 (UTC)
    • Quoting from the article (emphasis mine to facilitate reading):

"However, Campanian-Maastrichtian beds of Europe yielded isolated remains referable to Ornithocheirus (Ornithocheiroidea; see Wellnhofer 1991) and other non-azhdarchid taxa (Jianu et al. 1997; Barrett et al. 2008), and Campanian- Maastrichtian beds of USA and Brazil yielded fragmentary specimens of pteranodontid-like taxa and Nyctosauridae, respectively (see Company et al. 1999). Additionally, a nearly complete rostrum from the Maastrichtian of USA was recently assigned to the Tapejaridae (Kellner 2004). To these reports, here we add the non-azhdarchid Piksi barbarulna, also from USA. In conclusion, the current record of the Pterosauria is suggestive of a large diversity of Late Cretaceous pterosaurs, probably comparable to that of Early Cretaceous times"

Why people keep insisting in deliberately missing this part? — Preceding unsigned comment added by Chaoyangopterus (talkcontribs) 18:53, 31 December 2012 (UTC)

Emphasizing campanian doesn't help your case, since that is further from the Cretaceous–Paleogene extinction event which is why I avoided it. It is important to this subject, if a species is found dated to the Maastrichtian, but not the Campanian. I was trying to get your text inserted, and I didn't miss anything. Sidelight12 Talk 19:36, 31 December 2012 (UTC)

    • Fair enough. But the Maastrichtian proper fossil reccord is minimal, and most of the content in the main page is equally speculation from late Campanian fossil sites. - Chaoyangopterus, 31 December 2012
  • I think this last addition can be deleted. It does, however, seem to clarify the paragraph before it. It would contradict it, except the part "Smaller pterosaur" is rather vague. Sidelight12 Talk 18:07, 1 January 2013 (UTC)

Error: Bad DOI specified[edit]

In the template for reference #56 (Agnolin, F. L. (2012), "Systematic reinterpretation of Piksi barbarulna Varricchio, 2002 from Two Medicine Formation (Upper Cretaceous) of Western USA (Montana) as a pterosaur rather than a bird))", Varricchio, D. (Muséum national d'histoire naturelle, Paris)) please change |doi=http://dx.doi.org/10.5252/g2012n4a10 to |doi=10.5252/g2012n4a10. Thanks Illia Connell (talk) 03:53, 1 January 2013 (UTC)

Done. :) Firsfron of Ronchester 04:17, 1 January 2013 (UTC)
Thanks Illia Connell (talk) 04:59, 1 January 2013 (UTC)

Unconstructive new changes[edit]

IP 65.74.88.104, and new editor Chaoyangopterus appear to be single-use accounts who have been making major changes to the article that are disruptive. Discuss them here first before making the changes, otherwise these changes are going to RfC (and ANI if non-cooperative) for community review. - M0rphzone (talk) 09:04, 14 January 2013 (UTC)

I don't have a problem with most of the changes, which added sourced content to the article. The only one I would have reverted was the last one, which removed sourced content from peer-reviewed articles. The Ojo Alamo material is contentious, but it's not "pure nonsense". Firsfron of Ronchester 09:15, 14 January 2013 (UTC)
I added some things because I am familiar with the literature (but not how to use the talk pages). In my opinion, the page would benefit by updating it to reflect the latest literature. For example, studies published in the past few years show that both fish and lizards suffered major extinctions at the K-Pg boundary, and the article would benefit from updating it to reflect this. Likewise, the pterosaur edits (not mine) reflect new knowledge about pterosaur diversity. I think the author overstates the case, but their basic point- late Cretaceous pterosaur diversity is underestimated, so maybe more things go up to the K-Pg boundary than we thought- is valid. This is the kind of thing that improves the article.
Last- and perhaps more controversially- I think the article would benefit by presenting the evidence for the asteroid impact in more detail. This would include a brief summary of evidence for impact (iridium and other metals, spherules, shocked quartz, tsunami deposits), the proposed physical effects of the impact (darkening and cooling, wildfires, acid rain, etc.) and the logic linking the extinction to the impact: the Chicxulub event is the only event that has been shown to occur simultaneously with the extinctions (Deccan traps start before, final regression of the Western Interior Seaway happens after). 33 years ago, the asteroid impact would rightly have been considered a minority view with limited evidence, and (rightfully) given a paragraph or two. Now, it's the favored hypothesis (the Schulte et al. 2010 paper has several dozen authors, which was done deliberately to emphasize the broad support). Overall I focused on adding (including about 20 references, many recent) and re-organizing rather than deleting.
Concerning the deleted references, I did my best to preserve references. In several places, however, the cited papers aren't actually relevant to the point being made. For instance, reference 63 (Ryan et al.) does not refer to Late Cretaceous dinosaur diversity, but instead to Centrosaurus taphonomy (the relevant reference would actually be Sarjeant and Currie 2001). Likewise reference 62 refers to plant remains, not dinosaurs. Reference 56 refers to Early Cretaceous birds, not Late Cretaceous birds. Check the paper abstracts- these papers aren't relevant to the article. Either the correct reference needs to be located, or these need to be deleted. --- anonymous editor — Preceding unsigned comment added by 65.74.88.104 (talk) 10:50, 14 January 2013 (UTC)
okay... have discussed what I am up to. Since there's no commentary, I assume we have "consensus" and can add these edits back in? No explanation was given for why these edits or adding new, more up-to-date references and correcting inaccuracies is considered disruptive -anonymous — Preceding unsigned comment added by 65.74.88.104 (talk) 05:26, 15 January 2013 (UTC)
Thanks for your work. I haven't checked every source, but the material you've added looks reputable and well-sourced. I've gone ahead and added all of your edits back in, with the exception of the Ojo Alamo stuff, which you removed with the edit summary deleted stuff on Paleocene dinosaurs- this is considered nonsense. The paragraph actually discussed the claims made and countered them with more recent arguments, which seems pretty balanced and WP:NPOV to me. All three sources cited (Sloan et al (1986), Fassett et al (2001), Sullivan (2003)) in general support the material (though the measurements sourced to Sloan's work need fixed). Please continue with your good work, but be careful not to remove carefully-sourced material. Firsfron of Ronchester 06:03, 15 January 2013 (UTC)
Given that the newest official geological timescale defines the Paleocene beginning 66 Ma ago, and most recent sources consistently date the impact crater/upper Hell Creek/Lance etc. to about 65.5 (not sure if the margin of error is +/- 0.5 Ma), Paleocene dinosaurs may suddenly have been re-defined into existence! MMartyniuk (talk) 17:11, 15 January 2013 (UTC)

K-T boundary or K-Pg boundary?[edit]

It seems strange to me that the article consistently uses 'K-T boundary'. Our article has been moved to Cretaceous-Paleogene boundary, so shouldn't we change all these instances to 'K-Pg boundary'? Mikenorton (talk) 19:17, 14 January 2013 (UTC)

What the ever living….?[edit]

What happened to this great article? A bunch of opinion has been interjected (I've deleted)? Badly formatted citations? Nonexistent citations (I searched for one in Nature, which is not exactly a journal that hides it's articles deep in some Russian vault somewhere)? Uncited drivel. And then there's this pterosaur stuff based on ONE primary research article for which I could find no other supporting citation. Should we not at least pretend to be somewhat scientific and deprecate primary research?

Nevertheless, I'll accept consensus here (which appears to be four people, one of which is the SPA, and leave the silly Pterosaur section in there, even though giving weight to that one tiny clade is really odd. Shall we discuss every clade of mammal too? No, because the article would go on for 12 GB.

Anyways, I'm cleaning up this mess. It's typical of what's going on at Wikipedia. Experienced editors no longer are around, and amateurs can write whatever they want, and few care any more. Well, I care about this article, because I cite it a few times a day as an example of what Wikipedia does right. I don't want to be proved wrong. Ack. SkepticalRaptor (talk) 19:27, 17 January 2013 (UTC)

This deletion was because the citation was wrong. However, I finally found it as a "letter" to Nature, which indicates it was not peer-reviewed. No further publications were found, which means it never was sent in for publication and peer-review. I need to ask if anyone reviewed the citations from the recent massive changes? Because I'm not seeing it.SkepticalRaptor (talk) 19:36, 17 January 2013 (UTC)
I agree the pterosaur section seems out of place. One editor here is extremely persistent and for some strange reason has a huge vested interest in promoting any tenuous suggestion that the group was not in decline before the K/Pg (maybe thinking this would make them somehow inferior?). The details of whether or not the pterosaurs were in steep decline before the K/Pg seems irrelevant to the topic of the article, as the fact that they persisted to the boundary and died out for good in the extinction is not controversial. MMartyniuk (talk) 20:10, 17 January 2013 (UTC)
I have a problem with some of your removals, SR. In this edit, you remove cited content with the edit summary Deleting. Did anyone actually check the existence of these citations? So far, I'm finding that these cites are invented. A quick search pulls up the paper in question. Several other similar edits of this nature have been made today. It doesn't appear that you're checking before removing cited content. Firsfron of Ronchester 21:27, 17 January 2013 (UTC)

No longer Featured Article quality[edit]

I don't know when the article became like this (probably a couple years ago), but this is now far from being a featured article. The "Chicxulub Asteroid Impact" and "Alternative Hypotheses" sections are written in a synthesized, vague, and unsophisticated manner, and should be rewritten with all uncited claims removed or cited with reliable sources.

For example, the second paragraph of the Evidence For Impact section is completely uncited and makes various vague claims in an inappropriate writing style. The paragraph starts off with

"The impact hypothesis was viewed as radical when first proposed. However, more evidence was soon uncovered."

What the hell is this? Viewed by whom? Why aren't these sentences combined into longer sentences? What evidence? Where are the citations? A lot of sentences in this article can be combined or deleted altogether for being redundant.

The paragraph under the Alternative Hypotheses section is vague and full of weasel phrasing, and needs a citation. It looks like there originally wasn't a paragraph under the section, but someone added it in. Who the heck is managing/editing this article? Either clean it up, or I'm removing it.

All these paragraphs need to be rewritten in a more direct, specific, and more complex style. Also, why are the section headings not in title case? Look, I can fix some of these myself, but I'm just bringing up some of the numerous issues with this article. Maybe we should do a featured article review, and determine if this article is FA quality. I have a feeling that this will be speedy delisted at the state it's in now. - M0rphzone (talk) 03:17, 18 January 2013 (UTC)

evolution of animals based on the K-Pg "mass extinction" Wheller007 (talk) 04:58, 5 February 2013 (UTC)[edit]

I'd personally call it a mass death causing a mass evolution of what was left alive event.

Look at how animals left on islands dwarfed themselves as compared to the mainland animals of similar types. This is because the lack of sufficient food supplies to keep the large animal alive. Now imagine the same type of thing happening over millions of years to the dinosaurs and you'll see they didn't die out completely, they survived and dwarfed themselves. I personally have a flock of 50 dinosaurs that I feed daily. You would call them wrens but I call them "my kids".

I can see it in my own mind what happened once I thought of it and due to the lack of a space to suggest ideas like this, I'm suggesting them now. As far as not finding anything at all to prove anything, I come back with this challenge "find me proof that there was enough of a population that a certain breed of dinosaur that they were able to survive instead of being a simple fluke of nature here and there". The idea is they can't prove there was enough to make a breeding area (except in China and only one species of raptor) and under the same conditions they can't even prove my theory but mine actually makes perfect sense.

signed... Wheller007 (talk) 04:58, 5 February 2013 (UTC)

Science (journal)[edit]

Iridium[edit]

The boundary clay shows high levels of the metal iridium, which is rare on Earth but abundant in asteroids

Is this true? As I recall Iridium is a trace metal in both asteroids and the Earth. In asteroids it is many times more common, but still a trace amount?

I suggest this be restated. Jokem (talk) 02:54, 20 February 2013 (UTC)

Impactor a comet[edit]

current Nature has this as a featured article, claims errors in measurement of global iridium layer. 76.180.168.166 (talk) 00:15, 24 March 2013 (UTC)

Common ambiguity in earth science texts[edit]

'75% of animals and plants went extinct". Individuals, species, families? — Preceding unsigned comment added by 84.120.150.177 (talk) 18:58, 11 April 2013 (UTC)

Vandalism: Deletion Without Explanation[edit]

The section, "The Simplest Model and the Rule of Occam's Razor", which is "probably" the solution to the entire K-Tr mystery, is being deleted without explanation. This defines Vandalism. DO NOT delete unless you can state your JUSTIFIED reasons!

Remember: No matter who you may think you are, or what position you have managed to secure -- you are a VANDAL by NATURE if you delete without civilized explanation. No doubt, in your true capacity, you cannot think of one.


206.45.229.10 (talk) 22:50, 11 June 2013 (UTC)

The "uncited" bit is certainly well-founded: there are only three citations, none of which are particularly helpful for the main thrust of the section. The first appears to be a personal site with as much interest in selling posters and books as putting up any useful information about ammonites, the second is the definition of Occam's Razor, and the third concerns coelacanths. The "speculative" charge is not entirely fair, because the basic idea, at least for vertebrates, is part of Robertson et al. (2004)'s work, albeit certainly not described as done here. Long thoughts short: to be included here, the passage should include more relevant citations and should have a less melodramatic tone.
Cited: Robertson DS, McKenna MC, Toon OB, Hope S, Lillegraven JA (2004). "Survival in the first hours of the Cenozoic" (PDF). GSA Bulletin 116 (5–6): 760–768. doi:10.1130%2FB25402.1 J. Spencer (talk) 00:10, 12 June 2013 (UTC)
Nevertheless it would be unprofessional in the extreme to delete a model which explains the entire event down to the last known species and yet retains the utmost simplicity! However it is expressed, the proper way ahead here would be to edit in order to address any expressional (and referential) shortcomings -- but never to delete!! For as long as there in common sense in science, (the model which explains all is also the simplest), the probability will be too great that you just deleted the correct solution! 206.45.229.10 (talk) 01:18, 12 June 2013 (UTC)
Removed again, please read WP:OR, WP:SYN, WP:RS and WP:BRD. Vsmith (talk) 01:34, 12 June 2013 (UTC)
A Wikipedia article should report and cite academic research using a neutral tone. Giving your own views without relevant citations is original research, which is forbidden. Dudley Miles (talk) 10:53, 12 June 2013 (UTC)

K-Pg extinctions occurred within hours of impact, not months, years, or decades?[edit]

This is my first interaction here. Please take it easy on me! Being brief and to the point: is there a reason why the ideas of H. Jay Melosh are not included in this article? He is apparently well respected and is an expert in impact cratering. His idea is that essentially all surface life died within HOURS of the impact. The normal view is that the impact lofted dirt, dust and ash into the atmosphere, stopping photosynthesis, and successively killing off the herbivores then the carnivores which depended on them, in a time period extending into months, years, or decades. Dr. Melosh's view is that the ejecta from the impact was a very hot gas (?) but cooled when it hit space. It condensed in space and fell back to earth (worldwide). The heat generated by its reentry raised the air temperature of the earth up to as much as 1200 degrees Fahrenheit, broiling all unprotected plants and animals. This process would have occurred within only a few hours of impact (I've heard between 2 and 6 hours). Burrowing animals and some cave dwellers could have survived, as well as plant roots, since dirt is a good insulator.

Is this considered a "fringe" view and not worthy of inclusion in the article, or has no one gotten around to adding it? I'd consider working on it (if others considered it an acceptable addition), but I was hoping to start with something far simpler as my first edit in Wikipedia. Jharvey963 (talk) 17:36, 15 December 2013 (UTC)

Contradiction over acid rain[edit]

The article says both that the acid rain produced was minor, based on a 2003 source, and that a 2008 paper argues the acid raid was worse than previously thought due to refined impact location and ocean depth calculations. Has this since been resolved? Either way, this could be phrased a lot more smoothly. -- Beland (talk) 19:15, 27 December 2013 (UTC)

Bias towards asteroid theory[edit]

When this article was given FA status in 2007, it was cautious about the cause of the extinction, but it has now been changed to "it is now generally believed that the K–Pg extinction was triggered by a massive comet/asteroid impact". My impression from my reading is that scientific opinion has moved the other way since 2007, towards multiple causes. What do other editors think? Dudley Miles (talk) 10:38, 28 February 2014 (UTC)

Different editors think different things, but since 2010, they believed a meteor shower killed the dinosaurs, because now, 2 massive craters have been found, both in Ukraine and Mexico. This means even when Hateg Island had animals, the top predators also died out.Jk41293 (talk) 17:04, 1 July 2014 (UTC)

To preserve a NPOV, it's important that we are biased to the scientific consensus. Though respected scientists have proposed a an alternative hypothesis about the extinction of the dinosaurs, we need to remember two things. First, this article isn't about the extinction of the dinosaurs, although that's the popular reason why someone would read this article. Second, the numbers of scientists who support the alternative point of view are small in number. If the scientific consensus shifts towards other causes, this article should shift. But seriously, in the 7 years since this article became FA, the consensus has shifted much more strongly towards the bolide impact event. Dinosaurs were dying out prior to the extinction event, but they weren't extinct. the K-Pg event is a geological event after which we see a huge reduction in species, and it can be tied pretty directly to a bolide. SkepticalRaptor (talk) 18:57, 3 July 2014 (UTC)

Conflicting Info Over Mammalian Diversification Post Extinction[edit]

Under the "Extinction Patterns - Mammals" section, it states that "Current research indicates that mammals did not explosively diversify across the K–Pg boundary, despite the environment niches made available by the extinction of dinosaurs.[93]". However, in the "Recovery and Radiation" section, it states that "After the K–Pg extinction, mammals evolved rapidly to fill the niches left vacant by the dinosaurs."

The information seems conflicting, while stating both as absolute fact.

146.1.1.3 (talk) 19:49, 14 March 2014 (UTC)

65 million years ago or 66?[edit]

I found [2] linked on the Chixculub crater page, claiming the impact and extinction event to be 66 million years ago. 65 million is certainly found in a plethora of articles outside wiki - probably more than 66 - but if it is in fact outdated and we have a more precise measurement (and I'm hardly an expert on the topic) I think the article should be updated. 209.6.166.24 (talk) 00:03, 1 October 2014 (UTC)

  1. ^ Agnolin, F. L. (2012), Systematic reinterpretation of Piksi barbarulna Varricchio, 2002 from Two Medicine Formation (Upper Cretaceous) of Western USA (Montana) as a pterosaur rather than a bird)), Varricchio, D. (Muséum national d'histoire naturelle, Paris): 891&892, doi:http://dx.doi.org/10.5252/g2012n4a10 Check |doi= value (help), retrieved December 31, 2012 
  2. ^ http://www.bbc.com/news/uk-scotland-glasgow-west-21379024